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Cad/Cam Crazy


#1

So I too was crazy about having a 3 axis mill. I basically now can
make all kinds of routers and mills from 300 dollars to what ever I
want to spend. There are ready available plans on the internet and
after hours of r&d I think I can say that its funny when I see a
$20,000 jewelry mill. I could buy a used haas cnc for that much that
could probably make tools and benchtops and etc. But I think you
haft to look at most things are centered around buying a package.
Software is the expensive part. I think it’s relative to who you are
and what you do. If you spend $1000 a week in paying for wax carving
you might want to get a roland or some other brand. If your
electro-mchanically inclined you might get a spur to build your own.
I dunno. The roland does have a scanning function built in which is
really nice.

I always tell people to get some hands on with this type of work.
It’s like the new tool on the market that someone gets to add with
there other million tools but they don’t use it or can’t use it
rendering it useless to them. The tools doesn’t make stuff up on
it’s own.

As for the backlash being better with a belt driven as compared to a
ballscrew, leadscrew driven machine I would say it depends on the
machine and the application. For wax carving it probably is ok.

I have ballscrews with ballnut’s that would only lose. 001+/- per
foot of travel. That’s why they cost so much.

There’s a lot of factors of that can shape what decision you make.
For instance,who are you gonna call for technical assistance when
your custom built machine doesn’t function. What if you can’t get the
same exact part and have to retrofit. It cost’s you time. right.

With a name brand you can get part’s probably next day. So if you are
in the middle of a job that’s due yesterday it might help to get with
a company that can keep you running. Bye all means I am not
discouraging the gadgetly inclined people here to not pursue making
there own machines just presenting the possibilities. If you say shop
time is $50 dollars an hour and you spend on and off 20 to 40 hours
building and trouble shooting a homebuilt cnc it would cost you
$2-4000+ there alone. My biggest hurdle is the cost of cam software.
I have used some freeware types and others. They cost the real money
and I am not a software writer so it has to be payed outright.

Cad software can go from basically free to thousands and some of the
jewelry related packages will help you save on time with their
libraries of jewelry findings etc. So again it’s relative. So good
luck out there!!

Daniel Wade
Infinities


#2

Building your own cnc mill gives you the ability to have the size and
need that you want. Ball screws are the best for accuracy. belt
drives work also but are used in longer table movements. connecting
the servo or stepper motors, depending on the speed might have to be
gear down and that’s where plastic belts come in they don’t stretch
much and there a cog belt, they eliminate back lash. That’s why they
use ball screw. These items can be found on Ebay or bought and
companies that specialize in that area. Buying direct from the
manufacture of the parts guaranties that you can get a replacement.
The table slide can be bought and give a high tolerance and min
resistance. the electronics are off the self items and the controller
software are cheap at this time the one company is still selling
license on there beta software. The most expensive cost in owning and
running a cnc mill or lathe. Are the Cam software to generate the
code. If you machine in more that three axis the cost rises.

I have built a 3 axis router that machine in a millions resolution
most all the parts came from Ebay. The electronics came from there
manufactures. When the machine goes down yes it cost me my hourly
rate which is cheaper than owning a factory machine. We own a 6
color printer and 1 day past the warranty went down. Called service
the cost was 165.00 per hour from conn he had to drive to the shop
time started from is start till he returned. He diagnose that it
needed a new print head and order it then went home scheduled a
return time at 165.00 per hour from conn till his return only to not
fix the machine but make excuses and need a return visit. If I hade
made the machine I would have know the problem and order the part.

I have design a mill that will mill wax as well as steel or harder
material it will have 5 axis capability. Roland builds a good starter
machine for a beginner and a person who machine on a part time bases.
taig, Model master and there is many more small mills that are being
built with good accuracy and are a bench top mill with the capability
to machine with small cutter The industrial machine are not made to
machine with small cutters or the rpm to do so.

I don’t think Cnc will ever replace pieces created by the artist by
hand, only gives a ability to mass produce a product with a
repeatability. Parts that are created by hand to me have character
and personality, I hate tolerances and lack of creativity with out
detail. Custom should be custom

Thanks Randy
AKA Enjen Joes


#3
Bye all means I am not discouraging the gadgetly inclined people
here to not pursue making there own machines just presenting the
possibilities. If you say shop 

The above is from Daniel, but I just want to be clear about my
thoughts on this. I have no objection to spending $100,000 on a
machine - that is if I had $100,000. My objection is being asked to
pay $20,000 for $5,000 worth of equipment, and it’s just not going
to happen. Some of them come with CAM software, some do not, or what
they do have is Mach3, which is $149.99 or even free. If you look
closely at some of the jewelry specific machines, though, all they
are is linear slides, aluminum tables and bodies, and a bolted on
store-bought spindle, and again they don’t even use servos, they use
steppers. The huge price tage is because of the nice looking package
and the name, but it’s still only $500 worth of parts. I’m still
thinking of the 4-axis taig on E-Bay (it’s a dealer) for $1,895 -
add ProtoWizard for $2295 and off you go…

http://www.donivanandmaggiora.com


#4

I’ve been biting my tongue long enough on the subject of mill prices
and costs. I was closely involved in the development, design,
manufacture, and sales of the milling machines from one of the
companies mentioned. They probably have more CAD/CAM systems out
there than anyone right now…very successful products. I was also
a beta tester on their CAD software as I was for Bob McNeel on the
original Rhino. I say this only so that you can understand that I
just might have accurate in this regard.

I just need to say that the cost “estimates” thrown out so far are a
bunch of hokum. A perfect example of a little knowledge being a
dangerous thing. I will only say that the landed and assembled cost
of this particular mill is close to $9,000, NOT including the very,
very considerable cost of on-going R&D, warranty service, training,
etc.

And guess what? No servos!! Doesn’t need them, that’s a shade-tree
mechanic talking, sorry, you earned that one. I know that goes
against the “popular wisdom”, but if you run the tests and look at
the results and understand the ENTIRE process, you’ll find servos
are not needed. Been proved over and over again, even the
manufacturers have stopped yapping about it (except the ones who
haven’t done the R&D because they can’t afford it).

I find it ironic that jewelers who are not afraid to charge 3-4X
markups would groan about a 2.5 markup on a piece of equipment that
is not only a tax-free purchase, but a complete write-off in the
year of purchase even if it is leased! And usually with built-in
warranty, free support for at least a year and an open upgrade path.
Do you provide that on your custom work?

I’m sure that most of you who have survived and prospered for a
couple decades or more know that you need to fearlessly charge for
your products. If you “overcharge”, you will lose market, maybe. But
many other things go into the cost of the product…and there are
different qualities of product. And, please, before some bleeding
heart jumps up to cry about the “unfairness” of a high markup, please
first agree to stop buying clothes and furniture where the markups
can be on the order of 5-8x, and HIGHER! Oh, do you use a cell phone?
How much do each of those minutes cost you? Do you know that the cost
of a satellite-carried cell phone signal, after all the costs of the
system are amortized, is less than 0.1 cent? Write this down: The
purpose of a business is to produce a profit. Period. Everything else
is ancillary.

I have seen many mills (most) that require the normal and standard
set-up and fixturing procedures which does take some time, often as
long as half an hour or more. How do you compare that to a two-minute
setup, a few mouse clicks and you can cut three different models, in
succession, from the same tube of wax, while you go eat lunch??
Sorry, no comparison. The time savings alone, over time, is worth a
lot. A lot. Those are the sorts of things that must be
compared…apples to oranges, if you will. I currently have zero
interest in mills or any of those companies, so nothing positive can
befall me of any of this, but it is unfair to compare a pile of
drives and beds with some of the very sophisticated table-top mills
out there, some with very costly proprietary electronics on board. A
MiniTech is NOT the equivalent of a ModelMaster or Revo. Does it
out-put the same product? If the person knows what they are doing and
has spent the time, money and frustrtion to climb a long curve, yes.
Are the features and ease of use of the other more expensive products
worth the investment? To many, apparently so. To some, no. But a
comparison based solely on price of chosen components is off-base,
just as a pricing comparison of your custom work would be if we
looked only at the cost of materials. Even after labor, there is
overhead. No different with machinery.

Wayne Emery


#5
I will only say that the landed and assembled cost of this
particular mill is close to $9,000 

Wayne, since I guess this is probably largely directed towards me -
And I assume this refers to the Revo 540. While there’s no doubt
that it’s a fair bit of machine, I just don’t buy it that it costs
$9,000 to make. I just don’t.

No servos!! Doesn't need them, that's a shade-tree mechanic
talking, sorry, you earned that one. 

That’s me. My understanding is that the closed loop feedback
inherent in servos is superior, and that they are also longer lived,
have more torque, and more reliable over time. But it is completely
true that I don’t know that much about them, and my understanding
could be wrong. This comes under the heading of “conventional
wisdom”, and I don’t pretend to be an expert about it.

I find it ironic that jewelers who are not afraid to charge 3-4X
markups would groan about a 2.5 markup on a piece of equipment
that is not only a tax-free purchase, 

Sorry Wayne, just plain wrong. The markup on a $10,000 diamond is
more like 10% or maybe 20-30% at retail. The markup on a $500,000
diamond will be in single digits, most likely. Most million dollar
necklaces cost at least $900,000 to make, or on that order. This is
pretty much the point.

In summation, Wayne, what you say is true - the Revo is a quality
machine, and ultimately if you want it you just have to pay the
price. The sales pitch about how much money it’s going to make me,
even though Gemvision wants a cut of that, I can do without. The
reality is, as you say, that if you don’t pay for it, you won’t get
it, and I get that. But I don’t have to like it, either.

http://www.donivanandmaggiora.com


#6

I’ve held off before but maybe I should chip in my 2c worth… My
cnc machine is home made and cost me about $200 to build. With it I
machine everything up to and including tool steel to the tight
tolerances I need for watchmaking. Granted I have a reasonable
workshop in which I could make parts for it but it is really quite a
simple construction. The X and Y slides are simply the cross slide
and topslide off a large lathe which I picked up in a local scrap
yard. These are already set at right angles to one another and form
a ready-made unit which gives me a movement of about 6" x 4" although
you could probably find a bigger slide if you needed more travel. 1
1/2 amp size 42 steppers (again salvaged) give me more than enough
power even though my screw and nut system is a bit tight. The screws
were just screwcut and polished on my lathe (10mm x 1mm pitch in my
case as I wanted good resolution and I work in metric) and the nuts
are ‘cast’ in situ using ‘Polymorph’ (Thermoplast, plastiform or
whatever name you know the low temperature thermoplastics as). I
made nut blocks out of brass with 2 x 15mm holes at right angles to
each other and fixed these to the lower parts of the slides having
disposed of the original scews and nuts. Then I mounted my new
screws to the top parts of the slides and, again using polymorph, I
made supporting ‘wedges’ by squeezing a blob of polymorph under the
unsupported end of the screws and then adjusting the position of the
screw while the plastic was still soft so that it was straight and
level. Now I removed these temporary ‘wedges’ and assembed the slide
so that the screw passed easily through the nut block and then put
the ‘wedges’ back in place. I warmed the nut block to get good
adhesion from the polymorph and oiled the screw with a bit of
silicone grease. Now I pressed polymorph into the cross hole in the
nut block until the screw was fully surrounded (this isn’t critical
as my first attempt didn’t get the polymorph right round the screw
and it still worked fine). Once it had cooled, the ‘wedge’ could be
taken out. The cross hole makes it easy to squeeze the polymorph
round the screw and also prevents the finished nut from turning. I
now have nuts which are totally without backlash, are resilient
enough to accommodate any slight irregularities in the screws (if
there are any), appear to be wear resistant and, to some extent at
least, self lubricating and which I know I can easily replace or
tighten up should the need arise at virtually no cost. The only
downside - if you can call it that, is that the nuts grip the screws
so tightly that there is a bit of friction but, as I said before,
the stepper motors easily overcome that and it has never been a
problem.

Best wishes,
Ian
Ian W. Wright
Sheffield UK


#7

John,

I understand yor oint, as well. Please also think about thing from a
larger perspective. The makers of “desktop” mills designed to be used
primarily in conjunction with recent softwares designed solely for
jewelry designs are very specific types of machines. While some of
the ModelMaster machines CAN work with metals, like the Revo and
others their real forte is wax and butterboard and metal/resin
materials. As such, they are pretty much specialty machines. And the
makers of all of them are quite aware that as as additive prototying
technology advances, the mills will grdaually be pushed to the back.
Never compeletely, but as additive prototyping becomes more
efficient, less costly, etc., it will grown and the mill market will
shrink. One of the major manufacturers predicted a 7-10 year life
span remaining for the technology, before sdditive RP simply takes
over that market.

Idon’t know if that’s an accurate assessment, timewise, but it is
under that “cloud” that a door of opportunity was seen by at least
two manufacturers, and they seized the moment and went through the
door. To be blunt, for those products to exist profitably, those are
the prices that need to be charged. Again, a MAJOR portion of the
price charged represents a hopeful return on the unbelievably
expensive R&D end. I’m sorry you don’t believe the 9K figure, but the
Germans don’t come cheap, especially when you are asking them to
CONSTANTLY make on-the-fly changes to the base prodcut from which the
Revo is manufacture. Shipping costs alone are impressive. Could it be
sold for less and be profitable? Yes. Will it be? Why? If you can’t
keep up with the demand, why would you lower prices? Does it make
good money for those who have invested. The answer is yes and no. If
you train well and USE it a LOT it will make money. If it just sits
becaue the purchaser “doesn’t have time”, well, it’s a boat anchor. A
very expensive boat anchor.

Other things that haven’t been discussed should bear some
consideration. A prospective purchaser should ask around to get an
idea of the efficiency of after-market support and the the
reliability of the machinery itself. I know something about that,
too, but will remain silent.

Let’s just say this…were I ready to spend that kind of money (I
was the FIRST purchaser of the REVO mill) I would look long and hard
at products from HAAS. They have been in the mill business for a
long, long time and have their bases well covered. They make, today,
a machine that will run circles around any other desk top mill and
will machine all metals very efficiently and much faster than the
types of mills jewelers are buying. It’s tool-chaning ability is
awesome and while it costs a LITTLE more than the others, it is in a
decidedly different class. The ability to efficiently and quickly
make molds from harder metals is a big plus…but, again, another
step learning curve.

And I will agree that many of the smaller mills out there COULD be
assembled by a knowledgeable machinist, but a really knowledgeable
machinist would know better than to try, unless it is some sort of
"kit". Hey, I can paint my house with a toothbrush, but…why?

In the end, there will always be people whose purchasing objections
cannot be surmounted, and that’s okay. We all DON’T buy for our own
reasons, and we really don’t need to justify them. But, one either
owns a tool or doesn’t. And the tool is either efficient for the
intended task or not. And the competition in YOUR business will not
go away. And when THEY gain a competitive edge (and CAD/CAM IS a big
compeitive edge) you might need to respond. You can dive in, go
another way, or do nothing. It’s your business, but I’d avoid the
latter. And I’ve seen the results from the low to midlle machines.
mediocre output that takes forever, and you need to learn to be a
machinist to run the darn thing. All that disappears with the higher
end machines and is worth every single penny.

Best of luck in whatever you do…

Wayne Emery